1. Field of the Invention
The present invention relates to an ink set and an image recording method suitable for image recording in which ink is ejected by an ink-jet method.
2. Description of the Related Art
With the rapid development of the information technology industry in recent years, various information processing systems have been developed and recording methods and recording devices suitable for the respective information processing systems have been put into practical use. In particular, ink-jet recording methods have been widely used because they are advantageous in that they allow recording on various recording materials, the hardware (apparatus) thereof is relatively inexpensive and compact, and they allow very quiet operation, and the like. By recording using ink-jet recording methods, it has become possible to obtain high quality, photograph-like recorded materials.
Ink jet recording methods using pigment inks containing pigments as color materials are generally considered to have excellent storability compared with ink-jet recording methods using dye inks.
When the moisture in the pigment ink evaporates and the pigment ink solidifies, the solidified ink does not re-dissolve. Therefore, the ink is likely to adhere to and form a deposit on a nozzle tip of an ink-jet head or the like, which causes ink clogging at the time of ejection, resulting in poor ink ejection. When the ink solidifies at a cap, a wiper, or the like, wiping or the like thereof is difficult, which increases the burden of a maintenance system.
As a method for obtaining images using the pigment inks, a method has been proposed in which printing is performed by ejecting ink droplets of inks containing a thermoplastic resin component to a recording medium heated to a temperature higher than the softening point of the thermoplastic resin, thereby obtaining images with no bluffing (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 8-283636, 10-110126, and 10-152640). Moreover, an ink-jet recording method including forming an ink image using an ink containing a resin emulsion having a minimum film-forming temperature of 50° C. or more on a transfer medium whose surface temperature is heated to be higher than the minimum film-forming temperature of the resin emulsion, evaporating solvent components of the ink image on the transfer medium, and transferring the ink image on the transfer medium to a recording medium has been disclosed (see, for example, JP-A Nos. 9-207424 and 7-32721).
In the system in which a pigment ink including a thermoplastic resin component or a resin emulsion having a high minimum film-forming temperature is used, the maintenance performance may tend to further deteriorate.
In order to address the above, a maintenance liquid for ink-jet recording containing a resin solvent having a solubility in water at 25° C. of 3% by weight or more in an amount of from 0.1% by weight to 10% by weight and a humectant in an amount of from 1% by weight to 50% by weight has been disclosed (see, for example, JP-A No. 2007-119658).